The present invention relates to an electric power tool.
In known electric power tools, for example rotary hammers, an electronic unit is provided to control and/or regulate a drive motor. The high temperatures generated during operation of the electric power tool can cause malfunctions. To avoid this problem, usually a cooling device is provided to extend the service life of the drive motor and electronic unit. The electronic unit according to the prior art is mounted directly in the air flow, which circulates around it and cools it. The problem with this design is that the electronic unit comes into contact with drilling dust, moisture, or conductive particles that are sucked in through an intake opening. This problem is particularly pronounced in overhead work. This considerably limits the service life of the motor because erosion in the rotor and stator occurs, caused by dust and/or drilling particles.
In a modification of the known electric power tool, two separate air conduits are provided, a first air conduit for cooling the motor and a second air conduit for cooling the electronics.
In European Patent Application EP 984 545 A2, for example, a fan impeller sucks in cool surrounding air via two separate air conduits and then, mixed together, blows it out from the electric power tool. The air conduits, which are separate on the intake side until they reach the fan impeller, circulate around a hammer mechanism and transmission in a first air conduit and circulate around the drive motor and electronics in a second air conduit. It is disadvantageous here that an intake opening associated with the second air conduit is situated upstream of the motor in the air conduit so that first the electronics, then the motor, and finally the rest of the machine is cooled, which significantly reduces the cooling capacity.